SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50c57d08b3b1669993b6695adfa6880285228b324c118a61edb8af1fc539171d' 
  AND token = 'Iwl0CTWriopD3Qy7MokhF8PnovtYyULLD3MUiCkI8U8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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