SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b770c93ec1cdabce6ce78d194aa79319dc00bf00738dd4cb1a94bf20004b878' 
  AND token = 'umxSK29oiS4PX/DmF7NVox4O0/tqyrzLeVaCdXEjpgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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