SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7402afac20086c1d379e8fa3d12b323e35a976722d6c2b44193aaa5bca92de82' 
  AND token = 'mAp97tnSgKPzicBQoE10N4kFuLqu5Hv9wufOdFVtgCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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