SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac3fe3ac6c8b57abfb7ef3f0d20792bdfd710dbbcb7d225b7aad076706df648e' 
  AND token = 'BYMgVwEJb5VbzB66ACEYDYOoq6WXH7bpVXVkZaRlhfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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