SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0673d9404a99acc47510a09d8ebaf41b807bc12bb99a520af07ec7e7bb7e3e8f' 
  AND token = 'dwYZQYnjDJr4zLFl4kHeWWhR2bE8+QrG2CUwnYw1e+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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