SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '511b490c04db3d20ce160520ee6e174f283e58c3d79fc772b7b1cba88c97234a' 
  AND token = 'pNgoOXtF1ueNwsotJbAqVVnBC6FXorBWpSFk/ODFhvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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