SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b27356f96a13c98a94f549e72adcc5bdc0efcff987dda6569f78cb1c013047b0' 
  AND token = '4sL8doupFzRQSAJU++rH1aGVRG72rJOzeRKk8fDNLiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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