SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a1a49ab3faef465c5fc54bd888bafa44c0d6833e7e823943275d8661dd3a9379' 
  AND token = 'k/k3AQuiLsOb8qAfdR+CvBwaaRgtZtcw0e1Cu3KwOw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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