SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8aa48ab92888228a65ed4ffabf5345d75e8843804a2d303e250f59cb7cd2765' 
  AND token = 'UOPN3d6JFcWAHbLjzhdGOzmbUjqm2k4ugqitbUQvFMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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