SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1f62e8c3dbf4a63657d0b1ff7dd1f694091a9d411d2a853360544c18731b4f' 
  AND token = 'oqM78Lkb5miJLMRSvY3H1DdO5QzWg2hUJxkQtuwaErg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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