SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c1e15c5a71027263ede4dabb6e3d65126f6d8c94cdaafa70aa8ef13078aa4b8' 
  AND token = 's2CYHA7eQQqpOVZrtf4uaDHHoCUEBXXtmK40DxuRuAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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