SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bfc70f378a4b0fabe03925027b2c7a590dd1ad116883ecaa146caceff61e5c4' 
  AND token = '2YHjZUVHHy2Y/MZDhKb5PGnOInsTXzkPAIN/8PLGlBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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