SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7c43f8f9f62bcd9cc34e6112657b899b80e1c1d921cbaf1e38da2429bd2e2c7' 
  AND token = 'u+a57hqapjDsJFbIPrK35TejjgtHZO9Mj/ZA4wNHWHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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