SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fe7aef637a9bc88659c3ff58865d62e20e23bf8c4136c516217b23729122727' 
  AND token = 'tAfgVbK7zCfWKlMUI9mvEqOwEfxESztaVzsTmyRoLMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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