SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec67fa5257148a4818b33bf531a364107d12d19066dd1b11c1e81b62e5702050' 
  AND token = 'YYZ7gAyXRIPyGXeIf0VJszXfufJhzFhVsUXA/qKacvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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