SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d8c9497f1fee4c5f359a7379323d3ed82421d424eab99d812e7fe6d06ff6075' 
  AND token = '7UP9xQ0+eIt0MK7PuE9CMT/5wpnla0v4ybPSUf7Q1Rw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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