SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e203c0e82613fc6bd528b7395d999bd238667851a20508f570c6229b41794267' 
  AND token = '8r6WuaXeZwokOOEBlDDZh2uhiLf4p6O+dayuuFfpNZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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