SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b91bda9c305615f1ecc3c0b04707d9a2f75e646a3d8cde23ff12055d37752674' 
  AND token = 'rldHvPbYW0qQwsS5UqjOsiGULiHyBpvVH/9G6UKm4yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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