SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5f00824914697efd12791eb3aebcd738338439571e14dccb4b52cea8c4020f6' 
  AND token = 'I0bZeCehPsNcjIZUZU4CjcajEkWS1y0EpH2XJAiBuz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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