SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66be49839e2223451f0795d2aa6d8f00d21617135d921955b7795fc4f7e3cd05' 
  AND token = 'oCLUIpAU2COWJAGBqmSfC+l6F+3C+ZWux8Bhcl8GRM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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