SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc2a4bc46732e3ed3eb0826c23d6fbaab7a06400ced0fff30524fedee4ea4d6' 
  AND token = 'yWP+9c1DCNfGWdOrWlcsV+BjdXzYsErn2QFTtrH+pj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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