SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21414b523bc3714122175ee862a00161b2b8fda2c31296636be45266bd2bb786' 
  AND token = 'llOex7qUCsHMtTi1/txRAtyO5UeVMCC0PgMV+epd2Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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