SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f43be968d5d4b57111feb8766af0b7be5bf88c6c17d80d9d8f227490a250328' 
  AND token = 'YsNDHxmSIgX9DoYRyW5B118SXjVXVwJz/mRIXKlEpqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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