SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fbed4a5b4e09862587f7e031d6367e213d54e67572bf6a4c11f071c406cbcf21' 
  AND token = 'mIJz0kuvShrenn1kkQTnL1PpIYKHCNgjg+i/GRC78RE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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