SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d326472a0a5503acefa6aeb3cc362cdafeff61e80cc8775a92613a2feaf1df3' 
  AND token = 'DTFIifAPXGm2tKWhBtLZwzPgsxs6cXzpV3uXcU0oFz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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