SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4fd4628e09713f535c65f42a6d8f9fd095aeef02e65c44f1315e93f39bb8a3b' 
  AND token = 'e5ZY7EuVhoWHv3xKVIxKJWTJHqtq5/KzAVTzxz8iWiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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