SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc50f1c6af573359f206e0e668afa967b9dcd00cb630894c1b732d6830a8ce77' 
  AND token = 'VHCpIlwAYMhJCmmXt94LH4ea3LH8SmCW0xUnmZ6HvLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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