SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48dbe921df2bcfe899eee1d41295b40158d4fa27479fa4cff1e6244e347c4584' 
  AND token = '0viUXX5jbCW5Ygvjm+tpTWp8xRKON2NwB36EhXVmVpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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