SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cda0abed103444fc98c1abe8981a09929fd3ab95df166e73768acefc7c88bf8' 
  AND token = 'VTFlVm1s1MZenBqSlbisYTI0pgYtxJb3uCsTiMlLD+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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