SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35cba24ded271cec21ea09219a275374e4baf8b946518ceaf1e21cb57a9fa177' 
  AND token = 'kFopliO9pavkL98YN3NwUZ2K2OdCo+9SMpgplscbgBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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