SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '726395d26b410e0c66c6e201cab4f3082f537c790b6b6da8442fecc87c4f3379' 
  AND token = 'vrvvGFmKdyoCAx0klBgZIfY5CW0UqRiN5AZM887SX8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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