SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99df79711389f239e4e4a9da25413bafbc6773e0565be985f1c82b2177af5b74' 
  AND token = 'RGZO8nthUvzBAZs3YMMxXbktIkG/59mwbaiNoLVAGKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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