SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838eaad1727da1eef2c44a280961ff74460bdc6f2791413e010dfb2f3175e714' 
  AND token = '1rqalSsm+K6J2f+kXr2DLTxGxliP+0M4Rsbr2yS4kSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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