SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5024012878bdd2cc87a9615867949c8a1ab376f234e8477158f2d5ed59df7319' 
  AND token = 'k9umQV1twzfL8Igss5pv36upJS6Mql/fuAOHmHmNehI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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