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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e754aa2a318a89640a24000a46a420c1b7df6c305e7e432a675aad82111b88' 
  AND token = 'mkX499xcl3ct/AABpaY5YDPl1MIQriFN4a4qeQvvk6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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