SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc2c6439ef7a0201c69b65be27fd3d6d78a341a1119413f756197a6b0154c092' 
  AND token = 'Lzq7uPBVZ82j0RhYrSvcVP0j41vYvb8QHdVikQXvIzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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