SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8d59f2aeafe891aae3612c3e494b7fb622562be9e16c3d04d5c70a3187aa279' 
  AND token = '8O11WbABAs1AiiRvRYKqjVL8GacpWvFGXXwv4eIUPlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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