SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8b1942945530efac67609a2fb3699c5b483f05aa3ee1def1858ce3f01a7f07d' 
  AND token = 'wgqwFpiNnWExO/VZDJzfmikrYqBYD50cUEZ+cRRaDFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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