SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828bc1ce4d2165c64b598e6c605e3fec2d8f1c99f08042027b7115bca3d2b104' 
  AND token = 'EIsUQ3RtOW/o8P1+HP7RMBIfSrUNvdsVV3PldI5esAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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