SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d57e983d999517ef0f78575290fe2f3dc31664cf80742be8e48d46fb94e7e5c' 
  AND token = 'PiAC/5CTwtuZIkrJbCJmSjDosIyLcVMaRXlYGYBePi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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