SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e196d7e74c39f328c130d12686870ef4d935495f562299c295b503a57e13dae' 
  AND token = 'qJNtuqa+yPW0YrtiJFElvRlmbx+2Nn7mdsuXDcuJUgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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