SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c3f3dd2c2a8600113689bc88b36cd316a6e0f56719288c8a067e185dc8f9d3d' 
  AND token = 'JMutRot3GItpa/EFOWNxYTwEcoOz6t1ywEqBCgkEB+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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