SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b5aa387f6eeb76cd17bc52d6f1c35da515cffeff6b42df2b9c3b6c2f0b9dfbe' 
  AND token = 'BneyqO++BA1PRq7y6m/ir4tyzy+B1V1ejUqAV8UkcPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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