SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '77fd039a4e12f20484cd9bdc12d324abf91e365a9acddbeaf8859bba547d3bcc' 
  AND token = '5cZ4Zp48Vp0N75Ez42KXObq1UFnfSZEsUOC6UbFyKp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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