SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28ea9f0ffe81704f76a037d7128a35a815f3d758456d8795460bfd3636f02f64' 
  AND token = 'ocMzq4+8NgYRcmJytt+hrKh+3ULGfKouhM/y3hZww+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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