SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '531acf1cd96e1f34d0571322fe1155d92ed583b8813068bdd1990e10c79e581b' 
  AND token = 'JnrgKKT/vto+IZpQOCIzeek5mFe5REBFtK1rR4+G9U8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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