SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908fe1e185814697580ad4c13a1809cdd01889f44ed033fa2398175d5e2a020c' 
  AND token = 'OooC5tMdpoz5TwdzdI69sHl7EdAhsZd6aVH8HRLFIOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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