SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4526e530933da486bfe35de4431068692072e9925bfd19f2880adf33e2ff257' 
  AND token = 'AJJoDcQuSppRV3GBIJ4t0F5daWQNsUzJuEYrWsfEGyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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