SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '22ed8c88e982243550a4043453a92f3adb6e0484c7116bf5fd75d5c688d9e68b' 
  AND token = 'DL7gYFYNsAyPyQFnmkPOEfOfBelyVoYgysbjW3PVx/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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