SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ae0c11dd0d29bdadbdd28888e1ecf7f65616e09a1d77cf23495441cb504515a' 
  AND token = 'qkXH4aU/gwld6xf0ZVT8KsPRWxfTvIL7q1gsfnb4+VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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