SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f3d5d3ffd4f9712423735184d4a300afbd7da6cdd46b367c1bb29ea96d04ea5' 
  AND token = 'JNUosXqve32qZ1DNvwylGczL0++aPbAwFBFvq87MShU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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