SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f8d3c4af71b2699ea409c514fad0c32aa3109e87b0401c1654b1bd3c7897af' 
  AND token = '99XR5EMNWudTH3BMHpUg+CKpSRkw1dzW56fHN2SzkCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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