SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a9326423c450a7e2e492023d0b398876141a15b1bab9478a8e600da138576f2e' 
  AND token = 'LELJ2y50QGzY4wtmQ/5ZlhsDRdYC1KfRlAsej9z+hNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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