SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6c99c1473fb239174f4cf2dd4de019b2adefbab5eb7bff9d6aba34368036b3b8' 
  AND token = 'LHAlNtv5kcz4oRg86BZPs9jStcKjGVQbdxBgsKw/f08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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