SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47444506180a723d84f5e92c8c514f77ea384e6590f2f46399ed6353a393f5a' 
  AND token = 'v71FhTrxf9hK7vrSJ/aAiwPYRDiL/PjN9quZWlxQb9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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