SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc81fdfccda4d74e3de8dad3eb4ac0c9ca13d902c9eb2f2a73727ce66b30ad38' 
  AND token = 'zqNbI0eQFgehFxTEg0JBoQaXWFJVlfMl67D+jeGUejE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}