SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e1fa0b7e6ed5c5ff264254ef48760a73c1f2c24bde5792460a144872d26298' 
  AND token = 'F/+RL6CeWGMzJh0W0oHzLsOL7TBUkQLOCt8wu/XmwK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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