SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e6ea6a81f8264d43ea7cadc2f61d1f66e61cc7ae53671ffa804f13ce5608ea68' 
  AND token = 'a/DDw1EkyRWhcfpvuntXg4sA8/6RAkUaE4amALzY64U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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