SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fc7402998ad35dcaa161a3148182c3cad28af04a19a4185224113250418a79f' 
  AND token = 'LXQzrOZ4OHz24H2GizLkTn1ADqS2knkezU1UyuMPYKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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