SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33550a592b19cd0c5bc8ea7f109227f8d75590118b4d9989c084c1a786d853b1' 
  AND token = 'EfAFixBbUIIp3gk9ceKd1jbXu+4i/OCbpIg2VvtEizI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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