SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '283b4e1cbd62c74fb185cb01865d7e2af16ca23276fabf4e90f8530330e1abd8' 
  AND token = 'Ym5ChwiGjcVi4MNjOV5gh2Fu4KCwLkkisZdtzuwF6Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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