SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c672d07caf43e5048cee47285b2fedf79e0a0b870893c71b81077a834f34f5eb' 
  AND token = 'C75xwijdWWTMKYTZr3x/lwV3JONIFptOaROdaG0E81M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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