SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f8f51a580ae58ee58f5a5e55fe4d5bf1e41cfb8c7a840c4798b8ad8891bce9d' 
  AND token = '7pt7OgCAsVxB4HHCBfd++8qj7Z1MTKrMThMAyocxqUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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