SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b68c1be7352db1b3f5f0d6d14b06ffa4bf824893bb39d467a76590f7f4e589e2' 
  AND token = 'vup4vPqdZkuJuvQ2y8sBrCP1fX+RWY8wHf75lT/gDH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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