SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8b64f81a85a03779c5d769d84e47e605da8c38dee5f4157ad7f84ddc1f01ef' 
  AND token = 'mC6Uptv53J+LxnLsKbfjo9gJX4msmwCpg1PdlyvGZLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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