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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddf9c1a42330a69fd2f2c4d77ed4787c436705af593ffd2ec39945b0aa87aa2a' 
  AND token = 'sXvTqT3KYNfQLcNT8QBtelvC66MOAlyaSTvNEZ/fUDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}