SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10fe55f349899f374ccf9270266346e534c839bf8ef75b5ec9300520fa281d57' 
  AND token = '90M+NgwbJAN1W7eH/OJrCbudWpIt4BZqykJUHb2dSBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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