SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50821c02e896358f7e3f78f21523d5072ed6b7249e32f248b90d1d918bff39a5' 
  AND token = 'ilh00NTPjIaKXQiBlu5GzvkgN9ZoPVQiGR2WRBe+yXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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