SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c203618fc1658295e117947beacae9bc31c55ad48b02310870a11a222098b554' 
  AND token = '6Jufdw+8TEYFly9LX+svKDSL/Wqqrd3ieCDPJqtZD2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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