SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '689e12a49de836d6d9282bac7ea9c4c415e9217afb8dfacde864fc4625e35517' 
  AND token = 'h/pCLq+iaNL9f7OXIq9MdV0f2A7jYmVhsf7luU/q0VE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}