SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '62bf39c4873e2283955d76ad61cda95826e50950d603f2260f02e53ab50fde16' 
  AND token = 'taGwuJww9DW90KBgPZJ2JYbmp+T9LwKeCANza848lIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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