Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a78c948dbc130f8cb2be5bd36b2d9e542a008112129c9382d5b3a3a5a7a83291' 
  AND token = 'OjHeNoPvq92cXiZjjXEtjXbI3XCXtGB7o0TIArnmRlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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