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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ab8fc8fb3d3cd6e1e26df08b309c921fe198e46c6a91d6edd6105473c7b546' 
  AND token = 'WgWXuwPwOVnDQMYa9/t+exMkv8NszVeEaD6u+d1xsks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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