SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d18899dc99c1d4004bc69c63709317046cf7fc0dcb60acb44f39eb5f9ad809' 
  AND token = 'vBjDXOTBa++m5Ye1eIumJcPBu+xKUVVMhtyr7E6cvt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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