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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f477f4ff20c257a511ccd4ecc9b12f8eb8c1fd73cc0d2a5aeb66f9c8226e7a15' 
  AND token = '6u2/lFyAzBY1m65hxhhESh5zqeqK1GKTnS+0F2vud1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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