SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2de858b5b887282e65498b5c72168d7ad492fb02bff3b5f38cdbb0e0e3599a4' 
  AND token = 'UIWpCza8JqlYVemO35IOwsj21/d5kHdi1UMxhsltF8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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